The incorporation of fragments of the insulin molecule into IGF-I has previously been attempted in the form of two-chain disulfide-linked insulin-like structures. These molecules have considerably reduced biological activity relative to IGF-I and serum carrier protein binding is still significant rendering the in vitro activity of such compounds of little in vivo utility. See Joshi et al. Biochemistry 24: 4208-42 (1985); DeVroede et al. Proc. Nat. Acad. Sci.U.S.A. 82: 3010-14 (1985); and Joshi et al. Biochem. and Biophys. Res. Comm. 133: 423-429 (1985). The IGF-I analogs described in this invention are produced as single chain IGF-I-like molecules with equal potency to IGF-I at the type I IGF receptor and very little serum protein binding rendering such analogs of significant potential in vivo utility.